Adjustable support arm for audio visual device

ABSTRACT

An adjustable arm supports a device housing with respect to a base and allows the position of the device housing to be adjusted as desired. The adjustable arm has segments joined by pivot joints, with passages therethrough to allow wires to be strung through the arm segments and joints so as to be shielded by the arm. The joints can be either dual-pivot joints or single pivot joints, and for both types of joints, the frictional resistance of the joints can be adjusted. In some embodiments, the elements of the arm can be strung onto the wiring prior to assembly.

FIELD OF THE INVENTION

The present invention relates to an adjustable arm suitable forsupporting an audio visual device in a desired position with respect toa base.

BACKGROUND OF THE INVENTION

Small, individual audio visual devices are frequently used to provideboth entertainment and information to users. While such devices can behandheld, it is often desirable for the device to be positionable withrespect to a base to avoid a need for the user to hold the device in asuitable position for long periods of time.

One approach to supporting an audio visual device is taught in U.S. Pat.No. 6,104,443, which teaches a suspended television receiver or videomonitor. The television receiver of the '443 patent is mounted to apositioning mechanism that allows the user to place the televisionreceiver at a desired location and angle for comfortable viewing. The'443 patent discloses both a flexible gooseneck and a parallel armstructure where the parallel arms are connected to provide ascissor-type action as they are adjusted to position the televisionreceiver. A gooseneck makes precisely positioning the televisionreceiver difficult for a user, since the gooseneck can have a largeelastic component when bent, which will relax once the user releases thetelevision receiver. Alternatively, the gooseneck may be subject todrooping under the weight of the television receiver as the distancefrom the base increases. Additionally, a gooseneck is not well suitedfor readily moving the television receiver between viewing and storagepositions. The alternative positioning mechanism taught in the '443patent, which uses parallel arms, can pinch the user the position of thetelevision receiver is adjusted.

SUMMARY OF THE INVENTION

The present invention relates to an adjustable arm suitable forsupporting an audio visual device with respect to a base to allow theposition of the device to be adjusted so as to direct the visual displayand sound to the location of a viewer. The base typically rests on ahorizontal surface.

The adjustable arm has an arm first end and an arm second end, and theadjustability of the arm is provided by forming the arm with armsegments that are connected together with pivoting joints. The use of asegmented arm allows the localization of the movement to the pivotingjoints that connect the segments, and the concentration of the relativemovement allows finer control of the motion. Resistance to creep isprovided by frictional resistance between the elements of the pivotingjoints, and in some embodiments the degree of friction betweencomponents of the joint can be adjusted. In some embodiments, some ofthe arm segments are formed with multiple arm segment elements, in whichcase all of the arm elements in a given arm segment move as unit.

The arm segments and pivoting joints provide one or more continuousinternal paths of sufficient size to allow passing cables and/or wiresthrough the arm to convey power and/or audio visual signals from thebase to the device supported on the arm. The arm can be configured suchthat continuous wires can be passed through the arm elements.

In some embodiments, the pivot joints between the arm segments have dualpivot axes which are rotatably mounted with respect to each other androtate in planes with are parallel to each other. Each of the connectedarm segments in turn is pivotally mounted with respect to one of thedual pivot axes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view illustrating an adjustable arm which formsone embodiment of the present invention, which serves to support adevice housing at a desired position with respect to a base. In thisembodiment, the arm is constructed from a series of hollow arm segmentsconnected by adjustable joint assemblies having dual pivot axes whichare rotatable with respect to each other to provide three degrees offreedom between adjacent arm segments. This adjustable arm configurationis well suited for applications where power and signals are to beprovided from the base to the device housing by power and signal cables,since the arm provides a continuous passage along its length throughwhich shielded cables can be passed with sufficient shielding to preventinterference of the power with the audio/video signals. The adjustablejoint assemblies, with their dual axes which are adjustable with respectto each other, maintain the flexibility of the arm so that it can bepassed around obstacles; however, due to the localization of the pivotalaction, the arm can be easily readjusted and has a low susceptibility todrooping. This arm configuration is also readily foldable to facilitatestorage.

FIG. 2 is an exploded view showing details of one adjustable dual pivotaxis joint assembly that could be employed to connect two adjacent armsegments of the embodiment shown in FIG. 1. The adjustable jointassembly has a joint passage therethrough that allows for the passage ofa cable through the length of the arm and permits the cable to provideboth power and signals to the device housing via cords and cables,without requiring the cords and cables to pass outside the joint. Inthis embodiment, maintaining the cables internal relies on the stiffnessof the cables, and the frictional forces of the joint are not readilyadjustable.

FIG. 3 is an assembled view of another dual pivot axis adjustable jointwhich provides a range of motion similar to that of the adjustable jointshown in FIG. 2. The adjustable joint shown in FIG. 3 is designed sothat the frictional forces resisting movement of arm segments withrespect to each other and the frictional forces between two saddlebrackets are adjustable. This embodiment also has a flexible tube thatserves as a cable sheath for maintaining the cable within the confinesof the joint when the joint is flexed.

FIG. 4 is an exploded view of the joint illustrated in FIG. 3.

FIG. 5 is an exploded isometric view of another embodiment of a dualpivot axis adjustable joint of the present invention, which shares manyfeatures of the adjustable joint illustrated in FIGS. 3 and 4. Thisembodiment differs, in part, in the use of cowlings to assure that thecables are maintained within the joint. It also employs a quick releasecoupling for separation of two saddle brackets into which the armsegments are pivotally mounted.

FIG. 6 is a view of the adjustable joint of FIG. 5 when assembled.

FIG. 7 illustrates the adjustable joint shown in FIGS. 5 and 6assembled; however, in this view the cowlings are not shown.

FIG. 8 illustrates the quick release coupling employed in the adjustablejoint shown in FIGS. 5-7 when unassembled. FIG. 8 also illustrates twoalternative clips which can be employed in the coupling to adjust thedegree of friction between the saddle brackets.

FIG. 9 illustrates the quick release coupling shown in FIG. 8 whenassembled.

FIG. 10 illustrates the elements shown in FIG. 8 in an inverted positionto more clearly show the structure of the alternative clips.

FIG. 11 is an isometric view that illustrates another embodiment of theadjustable arm of the present invention. In this embodiment, theadjustable arm has rigid segments connected by single-axis pivot joints.The arm terminates in an arm first end, which is rotatably mounted to abase, and an arm second end, that is rotatably connected to a devicehousing. The arm has two intermediate sections having pivot joints thatare connected by a spring which counters the effects of torque createdby the weight of the device housing.

FIG. 12 is an exploded isometric view illustrating an adjustable armsimilar to that shown in FIG. 11, showing how the components of the armcan be strung onto wiring before the elements of the arm have beenassembled.

FIG. 13 is an assembled view of the embodiment shown in FIG. 12. In thisembodiment, the adjustable arm employs two springs to counter the weightof a device housing, one spring serving to bias the arm segment to whichit is connected against motion toward the device housing, and the otherspring serving to bias an adjacent arm against the downward force of thedevice housing.

FIGS. 14 through 17 are section views that illustrate varioussingle-axis pivot joints which are suitable for use connecting togetherarm segments in the embodiments illustrated in FIGS. 11-13, and whichallow adjustment of the frictional force required to pivot adjacent armsegments relative to each other.

FIGS. 18 and 19 are isometric views that illustrate an alternative jointassembly which can be used for connecting to an arm segment to which adevice housing is attached.

FIG. 19 shows the joint assembly in an inverted position to illustratepassages provided for passing wiring through the joint assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates an adjustable arm 100 which forms one embodiment ofthe present invention. The adjustable arm 100 serves to support a devicehousing 102 in a desired position and orientation with respect to a base104. The adjustable arm 100 is constructed from rigid arm segments 106that are pivotally and rotatably engaged with respect to each other withbi-pivotable adjustable joint assemblies 108 to provide foradjustability. Examples of structures that can provide these jointassemblies 108 are discussed below with reference to FIGS. 2-10. The useof the rigid arm segments 106 in the adjustable arm 100 allows fineadjustment of the adjustable arm 100 to position the device housing 102,since the freedom of motion is localized at the bi-pivotable adjustablejoint assemblies 108, which makes the adjustable arm 100 less subject tospring-back than continuously-adjustable structures for positioning,such as the traditional use of a flexible “gooseneck”. The freedom ofadjustability offered by using the bi-pivotable adjustable jointassemblies 108 in the arm 100 permits the arm 100 to traverse anon-planar path, allowing the arm 100 to be configured so as to passaround obstacles.

The adjustable arm 100 terminates in an arm first end 110 and an armsecond end 112. The arm first end 110 is affixed to the base 104, whilethe arm second end 112 is attached to the device housing 102 andincorporates a pivot coupling 114. The rigid arm segments 106 each havearm segment passages 116 therethrough, and the adjustable jointassemblies 108 each have a joint passage 118 therethrough to allowcables and power cords (not shown) to be passed through the adjustablearm 100 from the base 104 to the device housing 102. While the armsegments 106 are illustrated as being formed of rectangular tubularstock, other tubular shapes could be employed while allowing cables tobe passed therethrough. In the arm 100, wires and/or cables can bethreaded through the elements of the arm 100 either before or after therigid arm segments 106 and the adjustable joint assemblies 108 have beenassembled to form the arm 100.

Having the arm segments 106 formed as single elements has advantagesover the use of paired elements that are pivotably joined so as tochange their spacial separation as the arm is adjusted, such as istaught in U.S. Pat. No. 6,104,443. The adjustable arm 100 may beadjusted by the user without concern of being pinched when manipulatingthe arm segments, since the adjustable arm 100 does not have pairedelements in the arm segments 106 which could be brought into contactduring use as the user manipulates elements of the arm 100.

FIG. 2 illustrates one example of a bi-pivotable adjustable jointassembly 150 which could be employed to provide the joint assemblies 108in the embodiment illustrated in FIG. 1. FIG. 2 shows the adjustablejoint assembly 150 exploded. The adjustable joint assembly 150 providespivotal motion between an arm first segment 152 and an arm secondsegment 154, allowing pivotable adjustment between the arm segments(152, 154), as well as allowing rotation of the pivotal movement of eachof the arm segments (152, 154) with respect to the other about a bracketrotation axis 156.

The adjustable joint assembly 150 employs a first saddle bracket 158,which pivotably, slidably engages the arm first segment 152 and, onceengaged, is held there by friction forces either by direct contact ofthe engaging surfaces or through contact with an intermediate elementmaintained therebetween (this latter scheme being discussed below in thedescription of FIGS. 3 and 4). A first pivot pin 160 passing through thefirst saddle bracket 158 and through the arm first segment 152 providesa first pivot axis 162. Similarly, a second saddle bracket 164pivotably, slidably engages the arm second segment 154 and, onceengaged, is held by friction forces either by direct contact of theengaging surfaces or through contact with an intermediate elementmaintained therebetween. A second pivot pin 166 passing through thesecond saddle bracket 164 and the arm second segment 154 provides asecond pivot axis 168.

The saddle brackets (158, 164) are rotatably engaged with each otherabout the bracket rotation axis 156, and means are provided to maintainthe saddle brackets (158, 164) in frictional engagement. In theadjustable joint assembly 150 illustrated, the first saddle bracket 158has a saddle post 170 which rotatably, slidably engages a saddle passage172 in the second saddle bracket 164. A tie down bolt 174 threadablyengages the saddle post 170 and extends over the second saddle bracket164, serving to secure the two saddle brackets (158, 164) with respectto each other. As the saddle brackets (158, 164) are rotated withrespect to each other about the bracket rotation axis 156, the firstpivot axis 162 is rotated with respect to the second pivot axis 168.

The saddle post 170 has a joint passage 176 therethrough, which is ofsufficient size to accommodate cables and power cords (not shown)without binding.

Preferably, blocking means are provided to limit the rotation betweenthe saddle brackets (158, 164) to somewhat less than 360° to avoid unduetwisting of the cables and/or the power cord passing therethrough. Onesimple blocking means can be provided by a first block 182 extendingradially outward from the second saddle bracket 164 and a second block184 which is affixed to the first saddle bracket 158 and which ispositioned to engage the first block 182 as the saddle brackets (158,164) are rotated with respect to each other, this engagement serving tolimit rotation between the first saddle bracket 158 and the secondsaddle bracket 164.

The arm segments (152, 154) can be pivoted with respect to each other byapplying a force sufficient to overcome the friction between one of thearm segments (152, 154) and its associated saddle bracket (158, 164).Once readjusted, the arm segments (152, 154) are maintained in the newposition by friction between the saddle brackets (158, 164) and theirassociated arm segments (152, 154). Similarly, rotation between the armsegments (152, 154) is provided by rotation between the saddle brackets(158, 164). This rotation is provided by applying a twisting torquebetween the saddle brackets (158, 164) to overcome friction between thetwo saddle brackets (158, 164).

FIGS. 3 and 4 illustrate an alternative bi-pivotable adjustable jointassembly 200 which could be employed in an embodiment such as thatillustrated in FIG. 1. The adjustable joint assembly 200 is shownassembled in FIG. 3 and exploded in FIG. 4. The adjustable jointassembly 200 again provides pivotal and rotational motion between tworigid arm segments 202, but also provides protection against exposurefor cables and/or wires (not shown) passing through the adjustable jointassembly 200.

The adjustable joint assembly 200 has a first saddle bracket 204, whichpivotably engages one of the rigid arm segments 202 and is mountedthereto by a first pivot bolt 206. A first pair of friction washers 208are interposed between the rigid arm segment 202 and the first saddlebracket 204, and the first pivot bolt 206 can be tightened to compressthe first pair of friction washers 208 to vary the frictional resistanceto pivoting between the rigid arm segment 202 and the first saddlebracket 204. Similarly, a second saddle bracket 210 pivotably engagesanother of the rigid arm segments 202, and friction to resist pivotingis provided by a second pair of friction washers 212 and a second pivotbolt 214.

A flexible tube 216 is provided, which is better shown in the explodedview of FIG. 4. The flexible tube 216 has a joint passage 218therethrough, which provides a conduit for cables and/or wiring. In FIG.4, the flexible tube 216 is shown off to the side to more clearly showthe structure of the various components of the adjustable joint assembly200. The flexible tube 216 is sized to slidably engage a first bracketpassage 220 in the first saddle bracket 204 and a second bracket passage222 in the second saddle bracket 210. Interposed between the firstsaddle bracket 204 and the second saddle bracket 210 is a friction ring224 having a friction ring passage 226 through which the flexible tube216 also passes. The flexible tube 216 has a first bolt notch 228,configured to accommodate the first pivot bolt 206, and a second boltnotch 230, configured to accommodate the second pivot bolt 214. As thefirst saddle bracket 204 rotates relative to the second saddle bracket210, the first bolt notch 228 and the second bolt notch 230 rotate withthe saddle brackets (204, 210), twisting the flexible tube 216. Whilethe flexible tube 216 is sufficiently elastic to accommodate sometwisting due to rotation, this twisting may limit the rotation betweenthe first saddle bracket 204 and the second saddle bracket 210.

The saddle brackets (204, 210) are attached together by a pair ofbracket bolts 232. The bracket bolts 232 pass through bolt slots 234 inthe second saddle bracket 210 and through bolt passages 236 in thefriction ring 224, and threadably engage bolt receivers 238 in the firstsaddle bracket 204. Advancing the bracket bolts 232 in the boltreceivers 238 draws the first saddle bracket 204 and the second saddlebracket 210 together, compressing the friction ring 224 and increasingthe frictional resistance to rotation between the first saddle bracket204 and the second saddle bracket 210. The bolt slots 234 in the secondsaddle bracket 210, in combination with the bracket bolts 232, providethe means for rotatably engaging the first saddle bracket 204 with thesecond saddle bracket 210, and also provide blocking means to limit therotation between the saddle brackets (204, 210). This limits twisting ofthe flexible tube 216 and any cables and/or wiring passing therethrough.

FIGS. 5-10 illustrate another bi-pivotable adjustable joint assembly 250which provides pivotal and rotational motion between two rigid armsegments 252, as well as providing protection against exposure forcables and/or wires passing through the adjustable joint assembly 250.FIG. 5 is an exploded view of the adjustable joint assembly 250, whileFIG. 6 is an assembled view of the adjustable joint assembly 250.

The adjustable joint assembly 250 again has a first saddle bracket 254,which is pivotably attached to one of the rigid arm segments 252 by afirst pivot bolt 256. A first pair of friction washers 258 arecompressed between the rigid arm segment 252 and the first saddlebracket 254 as the first pivot bolt 256 is tightened to adjust thefrictional resistance to pivoting between the rigid arm segment 252 andthe first saddle bracket 254. A second saddle bracket 260 is pivotablyattached to another of the rigid arm segments 252 by a second pivot bolt262, and friction to resist pivoting is provided by a second pair offriction washers 264.

In this embodiment, a rigid tube 266 provides a conduit for cablesand/or wiring (not shown), and serves to rotatably engage the firstsaddle bracket 254 and the second saddle bracket 260. In thisembodiment, the rigid tube 266 also serves to attach the first saddlebracket 254 and the second saddle bracket 260 together. The rigid tube266 has a joint passage 268 therethrough, and rotatably engages a firstbracket passage 270 in the first saddle bracket 254 and a second bracketpassage 272 in the second saddle bracket 260, shown in FIG. 5.Interposed between the first saddle bracket 254 and the second saddlebracket 260 is a friction ring 274 having a friction ring passage 276through which the rigid tube 266 passes. The rigid tube 266 has a tubeflange 278 and a clip notch 280, as best shown in FIG. 8. When thesaddle brackets (254, 260) are pressed together with the friction ring274 compressed therebetween, the rigid tube 266 is passed through thesecond bracket passage 272, the friction ring passage 276, and the firstbracket passage 270 and is secured by a retainer clip 282 that slidablyengages the clip notch 280 on the rigid tube 266, as shown in FIG. 9.FIG. 7 shows the retainer clip 282, when engaged in the clip notch 280,and the tube flange 278 serving to maintain the first saddle bracket 254and the second saddle bracket 260 connected together with a degree ofcompression on the friction ring 274 positioned between the first saddlebracket 254 and the second saddle bracket 260.

The degree of friction between the saddle brackets (254, 260) could beadjusted by varying the thickness and/or the compressibility of thefriction ring 274. However, to allow the degree of friction to beadjusted after the elements of the adjustable joint assembly have beenstrung onto wires and/or cables, it is preferred to provide alternativeretainer clips 282′ (shown in FIGS. 8 and 10) that can be substitutedfor the retainer clip 282 to adjust the degree of compression of thefriction ring 274. While the retainer clips 282′ are configured toengage the clip notch 280 of the rigid tube 266, they each have agreater effective thickness (T₂, T₃) than the thickness T₁ of theretainer clip 282, as shown in FIG. 10. Due to this greater effectivethickness (T₂, T₃), the retainer clips 282′ draw the saddle brackets(254, 260) closer together when engaged with the clip notch 280,providing increased compression of the friction ring 274 andcorrespondingly greater friction between the saddle brackets (254, 260).A similar effect could be achieved by interposing a shim at some pointbetween the retainer clip 282 and the tube flange 278 of the rigid tube266.

Referring again to FIG. 5, a post 284 on the first saddle bracket 254passes through a post passage 286 in the friction ring 274 and engages aslot 288 in the second saddle bracket 260. The post 284 and the slot 288provide blocking means to limit the rotation between the saddle brackets(254, 260).

To protect any cables and/or wires from exposure, the first saddlebracket 254 is provided with a first cowling 290 having a first cowlingpassage 292 therethrough. The first cowling 290 is formed of a resilientcompressible material, and is configured to substantially fill openspaces in the first saddle bracket 254 as it pivots relative to therigid arm segment 252, as shown in FIG. 6. Similarly, the second saddlebracket 260 is provided with a second cowling 294 of resilientcompressible material, having a second cowling passage (not shown)therethrough and configured to substantially fill open spaces in thesecond saddle bracket 260. The coverage provided by the first cowling290 and the second cowling 294 can be appreciated by comparison of FIG.6, where the cowlings (290, 294) are shown in place, with FIG. 7,discussed earlier, where the cowlings (290, 294) are omitted to moreclearly show the interaction of the tube flange 278 of the rigid tube266 with the second saddle bracket 260.

FIG. 11 is an isometric view of an adjustable arm 300 which offers lessfreedom in adjustability compared to the arm 100 shown in FIG. 1, butwhich provides a continuous concealment of wires and/or cables as theypass therethrough so as to connect between a base 302 and a devicehousing 304 containing an audio visual display system 306. The passagesthrough the elements of the adjustable arm 300 are interconnected toallow wires and cables to be strung so as to provide shieldingtherebetween. The adjustable arm 300 is fabricated from rigid armsegments that include an arm first segment 308, an arm second segment310, an arm third segment 312, and an arm fourth segment 314. All of thearm segments (308, 310, 312, and 314) are provided with passages 316therethrough which, as noted above, allow for the concealment of videoand audio signal cables (not shown) and a power cord (also not shown)which provide power and signals to the audio visual display system 306.As discussed in greater detail below with regard to FIG. 12, this designalso facilitates assembly, and, more importantly, allows wires and/orcables to be passed through from the base 302 to the device housing 304without any splices or terminations, helping to preserve signal quality.

The arm first segment 308 terminates in an arm first end 318 and isrotatably mounted to the base 302. The arm first segment 308 ispivotably attached to the arm second segment 310 via a first hollowpivot joint 320 which has a cavity (not shown) therein for passage ofwires and cables therethrough. Examples of hollow pivot joints whichcould be employed are shown in FIGS. 14-17 and are discussed in greaterdetail below. The arm second segment 310 is also attached to a secondhollow pivot joint 322 which has a cavity therein for passage of wiresand cables therethrough. The second hollow pivot joint 322 also attachesto the arm third segment 312 and provides pivotal motion between the armsecond segment 310 and the arm third segment 312. The arm third segment312 in turn attaches to the arm fourth segment 314 via a third hollowpivot joint 324 to provide pivotal motion between the arm third segment312 and the arm fourth segment 314. Again, a cavity is provided in thethird hollow pivot joint 324 for passage of wires and cablestherethrough. The arm fourth segment 314 terminates in an arm second end326 that is rotatably mounted to the device housing 304.

In this embodiment, the first hollow pivot joint 320 has a first jointcentral region 328 that is frictionally engaged with two first joint endcaps 330. The arm first segment 308 is attached to the first jointcentral region 328, while the first joint end caps 330 are attached tothe arm second segment 310. The arm second segment 310 of the embodimentillustrated is formed by a pair of second segment members 332, one ofwhich is attached to each of the first joint end caps 330. Similarly,the second hollow pivot joint 322 has a second joint central region 334and a pair of second joint end caps 336. The second segment members 332of the arm second segment 310 are attached to the second joint centralregion 334, while the arm third segment 312 is attached to the secondjoint end caps 336. The arm third segment 312 is formed by a pair ofspaced-apart third segment members 338, one of which is attached to eachof the second joint end caps 336. The third hollow pivot joint 324 hasthird joint end caps 340, to which the third segment members 338 areattached, and a third joint central region 342, to which the arm fourthsegment 314 is attached.

The design of the arm 300 has particular utility since the paired armelements of the arm second segment 310 and the third segment 312restrict the rotational freedom of these arm segments with respect toeach other to avoid excessive twisting of wires and/or cables passingtherethrough. Furthermore, if the third segment members 338 are spacedapart by an arm member separation A that is maintained substantiallyless than a breadth B of the device housing 304, then the pair of thirdsegment members 338 reduce the likelihood of inadvertent twisting thatmight otherwise result from movement of the third hollow pivot joint324.

The adjustable arm 300 allows the device housing 304 to be supported ata desired position. While frictional engagement between the jointcentral regions (328, 334, 342) and the end caps (330, 336, 340) of thehollow pivot joints (320, 322, 324) can be sufficient to maintain theadjustable arm 300 in the desired position, it may be advantageous toconnect a tension spring 344 between the first joint central region 328of the first hollow pivot joint 320 and the second joint central region334 of the second hollow pivot joint 322 to counteract forces due to theweight of the device housing 304 and the arm 300 on the arm secondsegment 310.

FIGS. 12 and 13 illustrate an adjustable arm 400, which is substantiallysimilar to the adjustable arm 300 discussed above. FIG. 12 illustratesthe individual elements of the arm 400 (with the exception of twotension springs) before assembly, while FIG. 13 illustrates theassembled arm 400 with the tension springs. The arm 400 employs threepivot joints 402, each of which has a pair of end caps 404 thatrotatably engage a central joint element 406 when the pivot joint 402 isassembled, with friction washers 408 positioned therebetween.

To facilitate assembly, the elements of the adjustable arm 400 can bestrung onto a power cord 410 and a signal cable 412 prior to assembly.If the pivot joints 402 are of the type discussed below with respect toFIG. 15, the degree of friction can be adjusted after the arm 400 isassembled.

As can be seen in FIG. 12, the power cord 410 and the signal cable 412can be strung through an arm first segment 414, an arm second segment416, an arm third segment 418 and an arm fourth segment 420, as well asthrough the end caps 404, the friction washers 408, and the centraljoint elements 406. Once the power cord 410 and the signal cable 412have been strung through the respective elements of the adjustable arm400, the arm segments (414, 416, 418, 420) can be affixed to therespective elements of the pivot joints 402 and the pivot joints 402then assembled.

In this embodiment, all arm segments (414, 416, 418, 420) areconstructed from tube stock with the arm first segment 414 and the armfourth segment 420 being constructed with single tubes having largerdiameters so as to allow them to readily accommodate both the power cord410 and the signal cable 412 without creating interference between them.When formed from single tubes, the arm first segment 414 and the armfourth segment 420 should be kept relatively short to reduce crosstalkbetween the power cord 410 and the signal cable 412.

Preferably, the lengths of the arm segments (414, 416, 418, 420) areselected such that the arm 400 can be folded for storage with a devicehousing 422 positioned directly above a base 424. One way that this canbe readily achieved is by making the arm first segment 414 somewhatlonger than the arm fourth segment 420. It is also preferred for the armfirst segment 414 to have a greater cross section than the arm fourthsegment 420 for improved appearance and to provide stability for theadjustable arm 400. The adjustable arm 400 terminates in an arm firstend 426 and an arm second end 428, both of which are preferablyconfigured with rotational snap interfaces that are designed to snaprespectively into the base 424 and the device housing 422.

FIG. 13 illustrates a first spring 430 and a second spring 432 which arenot shown in FIG. 12. The first spring 430 serves to bias the arm secondsegment 416 against the moment created by the arm third segment 418, thearm fourth segment 420, and the device housing 422. The second spring432 serves to bias the movement of the arm third segment 418 against theweight of the device housing 422. Both the first spring 430 and thesecond spring 432 of this embodiment are connected to the arm secondsegment 416. It should be appreciated by one skilled in the art thatother configurations would be possible.

FIG. 14 illustrates one embodiment of a pivot joint 500 which could beemployed in adjustable arms such as those shown in FIGS. 11-13, andillustrates the connection of passages in the arm segments to allowcables and/or wires (not shown) to pass therethrough. The pivot joint500 has a joint central region 502 positioned between a pair of jointend caps (504′ and 504″). The joint central region 502 is affixed to afirst pair of arm members 506 (shown in phantom), while the joint endcaps (504′ and 504″) are affixed to a second pair of arm members 508(also shown in phantom).

The joint end cap 504′ is shown prior to engagement with the jointcentral region 502, while the joint end cap 504″ is shown after it hasbeen engaged with the joint central region 502 and secured thereto by anumber of set screws 510. Each of the joint end caps (504′ and 504″) hasan insert portion 512 which is sized to slidably and rotatably engage acentral passage 514 of the joint central region 502. The insert portion512 has a securing groove 516 and terminates at an annular end capbearing surface 518 on the joint end cap 504. The joint central region502 has a number of screw passages 520, each of which threadablyreceives one of the set screws 510. When the insert portion 512 of thejoint end cap 504 is forcibly inserted into the central passage 514 toalign the securing groove 516 with the screw passages 520, deforming anO-ring 522, the set screws 510 can be advanced to engage the securinggroove 516 to maintain the joint end cap 504 engaged with the jointcentral region 502 with the O-ring 522 compressed therebetween.

The joint central region 502 has a pair of central region bearingsurfaces 524, each opposed to one of the end cap bearing surfaces 518when the insert portion 512 of the joint end cap 504 is inserted intothe central passage 514. The O-rings 522 are interposed between each ofthe central region bearing surfaces 524 and the opposing end cap bearingsurface 518. The O-ring 522 is a compressible element which isresiliently compressed between the central region bearing surface 524and the end cap bearing surface 518 when the insert portion 512 isadvanced into the central passage 514 to align the securing groove 516with the screw passages 520. The compression of the O-ring 522 causes itto forcibly engage both the central region bearing surface 524 and theend cap bearing surface 518 to provide friction between the joint endcaps 504 and the joint central region 502 to resist rotationtherebetween. The degree of friction between the joint end caps 504 andthe joint central region 502 can be adjusted by varying the thicknessand/or compressibility of the O-rings 522 with respect to the separationbetween the end cap bearing surfaces 518 and the central region bearingsurfaces 524. However, this does not allow for adjusting the degree offriction in the joint after the elements have been strung onto wiresand/or cables.

The first pair of arm members 506 of this embodiment are both formed astubular members, each having a first arm member passage 526 thatcommunicates with the central passage 514 of the joint central region502. Similarly, the second pair of arm members 508 are also formed astubular members, each having a second arm member passage 528. Each ofthe joint end caps 504 has an end cap passage 530 that communicatesbetween one of the second arm member passages 528 and the centralpassage 514. Thus, cables (not shown) can be passed through the secondarm member passages 528, the end cap passages 530, the central passage514, and the first arm member passages 526 to allow power and/or mediasignals to be transmitted through the pivot joint 500. While the pivotjoint 500 illustrated provides two separate paths for cables to be run,it should be appreciated that in some applications only a single pathmay be required. The pivot joint 500 is well suited to stringing thewires through the components of the arm before assembly; however, asnoted, the degree of friction in the pivot joint 500 cannot besubsequently adjusted.

FIG. 15 illustrates a pivot joint 550 which shares many features incommon with the pivot joint 500 discussed above. However, the pivotjoint 550 allows the frictional resistance to pivoting to be readilyadjusted by the user, without requiring any substitution of parts, andallows the degree of friction to be adjusted after assembly. The pivotjoint 550 again has a joint central region 552 and a pair of joint endcaps (554′ and 554″) which are slidably and rotatably engaged with thejoint central region 552. The joint end caps (554′ and 554″) aremaintained in the joint central region 552 by a number of set screws 556that are threadably advanced in screw passages 558 in the joint centralregion 552. The set screws 556 engage grooves 560 in the joint end caps(554′ and 554″), as shown for the joint end cap 554″. In the pivot joint550, the screw passages 558 are inclined to a longitudinal axis 562 byan angle θ which is preferably about 45°.

The joint central region 552 of this embodiment has a pair of centralregion bearing surfaces 564. Each of the joint end caps 554 has an endcap bearing surface 566. Interposed between the central region bearingsurfaces 564 and the end cap bearing surfaces 566 are O-rings 568. Whenthe set screws 556 are advanced in the screw passages 558, the setscrews 556 forcibly engage a lead sidewall 570 of the groove 560 andthereby reduce a separation s between the central region bearing surface564 and the end cap bearing surface 566, compressing the O-ring 568. Thetorsional load required to rotate the joint end caps 554 relative to thejoint central region 552 is proportional to the compression of theO-rings 568, and thus can be adjusted by adjusting the position of thesetscrews 556. The pivot joint 550 is also well suited to stringing thewires through the components of the arm before assembly.

FIGS. 16 and 17 illustrate a pivot joint 600 which provides a differentscheme for securing a pair of joint end caps 602 (only one of which isshown) to a joint central region 604. The joint central region 604 has apair of grooves 606, each configured to accept a retaining clip 608which is rotatably restrained therein. A pair of joint couplers 610 areprovided (only one being shown in FIG. 17), each of the joint couplers610 slidably and rotatably engaging the joint central region 604 andbeing retained thereon by one of the retaining clips 608. The jointcentral region 604 terminates at a pair of central region bearingsurfaces 612. The joint couplers 610 each have female screw threads 614.

The joint end cap 602 has an end cap bearing surface 616 and male screwthreads 618. The male screw threads 618 are configured to threadablymate with the female screw threads 614 of the joint coupler 610. When somated, the end cap bearing surface 616 is opposed to one of the centralregion bearing surfaces 612. A compressible washer 620, shown in FIG. 16in an uncompressed state, is interposed between the end cap bearingsurface 616 and the central region bearing surface 612. As the malescrew threads 618 of the joint end cap 602 are threadably advanced inthe female screw threads 614 of the joint coupler 610, the joint coupler610 becomes forcibly engaged with the retaining clip 608, which in turnforcibly engages the groove 606 in which it resides. This forcibleengagement allows the compressible washer 620 to be forcibly compressedbetween the end cap bearing surface 616 and the central region bearingsurface 612 to frictionally engage the joint end cap 602 with the jointcentral region 604, as shown in FIG. 17. The degree of friction betweenthe joint end cap 602 and the joint central region 604 can be adjustedby tightening or loosening the joint coupler 610. This embodiment isalso well suited for pre-stringing the parts of the arm before assembly.

FIGS. 18 and 19 illustrate an alternate pivot joint 650 for connectionbetween an arm fourth segment 652 and an arm third segment 654. In thisembodiment, a hollow barrel member 656 serves as one element of thepivot joint 650 and has a pair of spaced apart openings 658 (shown inFIG. 19) for insertion of two arm members 660 that collectively form thearm third segment 654. The hollow barrel member 656 also has a centralopening 662 (best shown in FIG. 19) located between the spaced apartopenings 658. Preferably, the barrel member 656 has a central portion664 having a reduced cross section in which the central opening 662 islocated. A C-clip 666 snaps onto the barrel member 656 to becomefrictionally, rotatably engaged therewith. When the barrel member 656has a central portion 664 having a reduced cross section, the C-clip 666attaches onto the central portion 664. The C-clip 666 can have a passagetherethrough for insertion of the arm fourth segment 652, or could beformed integrally therewith.

While the novel features of the present invention have been described interms of particular embodiments and preferred applications, it should beappreciated by one skilled in the art that substitution of materials andmodification of details can be made without departing from the spirit ofthe invention.

1. An adjustable arm for supporting a housing with respect to a base,the adjustable arm comprising: an arm first rigid segment that connectsto the base and defines an arm first end; an arm second rigid segment;an arm third rigid segment; an arm fourth rigid segment that connects tothe device housing and defines an arm second end; a first pivot jointwhich connects said arm first rigid segment to said arm second rigidsegment to allow relative pivotable motion therebetween; means foradjusting the torsional load supported by said first pivot joint; asecond pivot joint which connects said arm second rigid segment to saidarm third rigid segment to allow relative pivotable motion therebetween;means for adjusting the torsional load supported by said second pivotjoint; and a third pivot joint which connects said arm third rigidsegment to said arm fourth rigid segment to allow relative pivotablemotion therebetween.
 2. The adjustable arm of claim 1 wherein said armrigid segments have arm passages therethrough, and said joints havejoint passages therethrough which provide communication between said armpassages.
 3. The adjustable arm of claim 2 wherein all relativepivotable motions lie in a common plane.
 4. The adjustable arm of claim3 wherein, said arm second rigid segment comprises an arm second segmentfirst member and an arm second segment second member which is parallelto and affixed with respect to said arm second segment first member, andsaid arm third rigid segment comprises an arm third segment first memberand an arm third segment second member which is parallel to and affixedwith respect to said arm third segment first member.
 5. The adjustablearm of claim 3 wherein each of said first pivot joint and said secondpivot joint further comprises: a joint central region attached to one ofsaid arm rigid segments; a pair of joint end caps attached to another ofsaid arm rigid segments, said joint central region rotatably engagingsaid pair of end caps; and a pair of resilient rings, each positionedbetween one of said end caps and said joint central region; and furtherwherein said means for adjusting the torsional load supported by saidpivot joint for each of said first pivot joint and said second pivotjoint further comprises: means for varying the position of each of saidpair of joint end caps with respect to said joint central region so asto vary the compression of said resilient ring positioned therebetween.6. The adjustable arm of claim 5 wherein said arm rigid segments andjoint elements are so configured that they can be assembled after beingstrung onto a power cable and a signal cable.
 7. The adjustable arm ofclaim 6 further comprising: at least one tension spring operablyconnected to one of said pivot joints and to one of said arm rigidsegments so as to counteract torques on said one of said pivot jointsdue to weight.
 8. The adjustable arm of claim 1 wherein, for at leastone of said pivot joints, said means for adjusting the torsional loadbearing capacity of said pivot joints further comprises: a first jointelement; a second joint element, said first and second joint elementsbeing mounted so as to pivot with respect to each other about a commonpivot axis; a friction element positioned between said first jointelement and said second joint element; and means for varying the forceof engagement of said first joint element and said second joint elementwith said friction element, thereby varying the torsional load bearingcapacity of said pivot joint.
 9. The adjustable arm of claim 2 whereinat least one of said pivot joints is a dual-pivot joint that furthercomprises: a first saddle bracket having one of said arm rigid segmentspivotally attached thereto and pivoting about a first pivot axis; asecond saddle bracket having another of said arm rigid segmentspivotably attached thereto and pivoting about a second pivot axis, saidfirst saddle bracket frictionally and rotatably connected to said secondsaddle bracket about a bracket rotation axis such that said first pivotaxis and said second pivot axis rotate in parallel planes, said jointpassage extending between said first saddle bracket and said secondsaddle bracket; and further wherein said means for adjusting thetorsional load supported by said pivot joint for each of said at leastone dual-pivot joints further comprises: means for adjusting thetorsional loads about said bracket rotation axis, means for adjustingthe torsional loads about said first pivot axis, and means for adjustingthe torsional loads about said second pivot axis.
 10. The adjustable armof claim 9 wherein each of said dual-pivot joints further comprises:blocking means for limiting rotation of said first saddle bracket withrespect to said second saddle bracket.
 11. The adjustable arm of claim 1wherein the housing supported by the adjustable arm houses an audiovisual display system, and further wherein the housing is rotatablyattached to said arm fourth rigid segment.
 12. A pivot joint for anadjustable arm, the pivot joint adjustably connecting together an armfirst rigid segment and an arm second rigid segment, the pivot jointcomprising: a first joint element affixed to the arm first rigidsegment; a second joint element affixed to the arm second rigid segment,said first and second joint elements being mounted with respect to eachother so as to pivot with respect to each other about a common pivotaxis; a friction element interposed between said first joint element andsaid second joint element; and means for varying the force of engagementof said first joint element and said second joint element with saidfriction element, thereby varying the torsional load bearing capacity ofthe pivot joint.
 13. The pivot joint of claim 12 wherein said firstjoint element is provided by a joint central region and said secondjoint element is provided by a pair of joint end caps that rotatablyengage said joint central region, further wherein said friction elementis provided by a pair of resilient rings, each of said resilient ringsbeing positioned between one of said end caps and said joint centralregion, still further wherein said means for varying the force ofengagement of said first joint element and said second joint elementwith said friction element is provided by means for varying the positionof each of said pair of joint end caps with respect to said jointcentral region so as to vary the compression of said resilient ringpositioned therebetween.
 14. The pivot joint of claim 13 wherein the armsecond rigid segment is formed by a pair of parallel second segmentmembers, each attached to one of said joint end caps.
 15. Adual-pivoting joint for an adjustable arm, the dual-pivoting jointadjustably connecting an arm first rigid segment to an arm second rigidsegment and comprising: a first saddle bracket frictionally engaging andpivotably attaching to the arm first rigid segment, said first saddlebracket having a first pivot axis, about which the arm first rigidsegment pivots; means for varying the force of engagement of said firstsaddle bracket with the arm first rigid segment; a second saddle bracketfrictionally engaging and pivotably attaching to the arm second rigidsegment, said second saddle bracket having a second pivot axis, aboutwhich the arm second rigid segment pivots; means for varying the forceof engagement of said second saddle bracket with the arm second rigidsegment; a joint passage communicating between said first saddle bracketand said second saddle bracket; a bracket rotation axis about which saidfirst saddle bracket and said second saddle bracket can rotate withrespect to each other; and means for rotatably and frictionally engagingsaid first saddle bracket with said second saddle bracket so as to allowrelative rotation therebetween about said bracket rotation axis.
 16. Thedual-pivoting joint of claim 15 wherein said means for rotatably andfrictionally engaging said first saddle bracket with said second saddlebracket further comprises: means for varying the force of thefrictional, rotatable engagement of said first saddle bracket with saidsecond saddle bracket.
 17. The dual-pivoting joint of claim 15 furthercomprising: a friction ring interposed between said first saddle bracketand said second saddle bracket; and means for limiting the position ofsaid first saddle bracket with respect to said second saddle bracket soas to apply a compressive force on said friction ring positionedtherebetween.
 18. The dual-pivoting joint of claim 17 furthercomprising: a first bracket passage through said first saddle bracket; asecond bracket passage through said second saddle bracket; a frictionring passage through said friction ring; and further wherein said meansfor rotatably and frictionally engaging said first saddle bracket withsaid second saddle bracket further comprises: a rigid tube passingthrough and rotatably engaging said first bracket passage and saidsecond bracket passage, and passing through said friction ring passage,said joint passage being provided through said rigid tube, said rigidtube having, a tube flange for forcibly engaging one of said firstsaddle bracket and said second saddle bracket, and a clip notch; and aclip for engaging said clip notch and for forcibly engaging the other ofsaid first saddle bracket and said second saddle bracket, said clipnotch of said rigid tube being spaced apart from said tube flange suchthat, when said clip is engaged with said clip notch, a compressive loadis applied to said friction ring, said tube flange and said clip therebyproviding said means for limiting the position of said first saddlebracket with respect to said second saddle bracket.
 19. Thedual-pivoting joint of claim 15 further comprising: blocking means forlimiting rotation of said first saddle bracket with respect to saidsecond saddle bracket about said bracket rotation axis.
 20. Thedual-pivoting joint of claim 18 further comprising: blocking means forlimiting rotation of said first saddle bracket with respect to saidsecond saddle bracket about said bracket rotation axis.